To assign constant values and XML fragments:

Drag the Assign Source Literal icon from the top right hand corner to the target node or the canvas (center pane). The Assign Source Literal dialog appears.
Enter the constant value or XML Fragment to be assigned.
Select Literal is XML Fragment if your constant value is valid XML.
Click OK.
If you had dragged the source literal to the canvas or center pane in Step 1, drag the source literal icon in the canvas to the desired target node. This maps the source literal to the target variable.

Note:

When you assign values to a particular Mediator property during event publishing, the assigned value does not get propagated to the subscribing event.

You can work around this issue by using transformations to include the property as part of the event body.
You cannot assign values to the jca.db.userName and jca.db.password properties on Oracle WebLogic Server because their data sources do not support setting the user name or password dynamically to the getConnection method.

Table 20-2 through Table 20-4 list the various possibilities of assignment on constants and properties, payloads, and headers of a message from source to target.

Table 20-2 Possibilities on Constants and Properties

Source	Target	Example
Property	Property	`<copy expression="$in.property.jca.file.FileName" target="$out.property.jca.file.FileName"/>`
Constant	Property	`<copy value="ConstantNameAssigned.xml" target="$out.property.jca.file.FileName"/>`

Table 20-3 Possibilities on Payload

Source	Target	Example
XPath Expression	Property	`<copy expression="concat('ExprPropMed','-',oraext:generate-guid())" target="$out.property.jca.file.FileName" xmlns:oraext="http://www.oracle.com/XSL/Transform/java/oracle.tip.pc.services.functions.ExtFunc"/>`
XPath Expression (below part level)	Property	`<copy expression="$in.body/imp1:request/ProductReq/Make" target="$out.property.jca.file.FileName" xmlns:imp1="http://xmlns.oracle.com/psft"/>`
Property	XPath Expression (below part level)	`<copy value="$in.property.jca.file.FileName" target="$out.request/inp1:request/ProductReq/Model" xmlns:inp1="http://xmlns.oracle.com/psft"/>`
Constant	XPath Expression (below part level)	`<copy value="ConstantModel" target="$out.request/inp1:request/ProductReq/Model" xmlns:inp1="http://xmlns.oracle.com/psft"/>`
XPath Expression	XPath Expression	`<copy expression="$in.body" target="$out.request"/>`
XPath Expression (below part level)	XPath Expression (below part level)	`<copy expression="$in.body/imp1:request/ProductReq/Make" target="$out.request/imp1:request/ProductReq/Model" xmlns:imp1="http://xmlns.oracle.com/psft"/>`

Table 20-4 Possibilities on Header

Source	Target	Example
XPath Expression (below part level)	Property	`<copy expression="$in.header.inp1_header/inp1:header/Name" target="$out.property.jca.file.FileName" xmlns:inp1="http://xmlns.oracle.com/psft"/>`
Property	XPath Expression (below part level)	`<copy value="$in.property.jca.file.FileName" target="$out.header.inp1_header/inp1:header/Name" xmlns:inp1="http://xmlns.oracle.com/psft"/>`
Constant	XPath Expression (below part level)	`<copy value="NewID.xml" target="$out.header.inp1_header/inp1:header/Id" xmlns:inp1="http://xmlns.oracle.com/psft"/>`
Constant	XPath Expression (below part level)	`<copy value="sampleusername" xmlns:wsse1="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" target="$out.header.wsse1_Security/wsse1:Security/wsse1:UsernameToken/wsse1:Username"/>`
XPath Expression	XPath Expression	`<copy target="$out.header.inp1_header" expression="$in.header.inp1_header" xmlns:inp1="http://xmlns.oracle.com/psft"/>`
XPath Expression (below part level)	XPath Expression (below part level)	`<copy target="$out.header.inp1_header/inp1:header/Name" expression="$in.header.inp1_header/inp1:header/Id" xmlns:inp1="http://xmlns.oracle.com/psft"/>`